1. Field of the Invention
This invention relates to polyethylene compositions for use in packaging. This invention particularly relates to metallocene polyolefin compositions comprising a heat seal modifier.
2. Description of the Prior Art
Polyethylene polymers are useful in packaging, as well as in other applications. The use of linear polyolefins is not without problems to a manufacturer, however. One problem that a manufacturer may be faced with is finding a proper balance between the cost of manufacture and the performance of the manufactured product. Linear polyethylenes produced using a single site metallocene catalyst can have many performance benefits. However, linear polyethylenes can also be difficult to process in a cost-efficient manner.
Moreover, linear (metallocene) polyethylenes can have less than desirable heat seal properties. That is, linear polyethylenes often do not provide sufficient adhesion between the sealing layers of polyethylene to result in a good adhesive seal for a package. Efforts to improve the heat seal characteristics of linear polyethylenes by blending them with other materials, such as ethylene copolymers with methacrylic acid or acrylic acid, have not had universal success.
Thus, it can be desirable to have a linear polyethylene composition which is more easily processible in the melt, and at the same time provides desirable heat seal characteristics for packaging applications.